Bruce,
I believe you.
I have found three styles under the radiator support. One type is a body shim incorrectly used.
The ones that look correct are ones that are the same areal dimensions as the rubber pad, and they are very thin. I have found as many as four of these shins under a radiator.
Here are some examples, ignore the non-radiator shims:
https://www.chevsofthe40s.com/shop/...p;dept=Truck&searchtype=FT&Go=Go